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Texas Instruments LP3958TL/NOPB
- Part No.:
- LP3958TL/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 25-WFBGA
- Datasheet:
-
LP3958TL/NOPB.pdf
- Description:
- IC LED DRV RGLTR I2C 25USMD
- Quantity:
- Payment:
- Shipping:
Inventory:250
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Product details
Overview
LP3958TL/NOPB from Texas Instruments is a lighting management unit (LMU) designed for portable electronics, integrating a high-efficiency 1 MHz magnetic boost converter and dual white LED backlight drivers plus three keypad LED drivers. It delivers up to 25.5 mA per MAIN/SUB string and supports 0–25 mA/LED on KEY1–KEY3 in constant-current or switch mode, operating from a 3.0–5.5 V input to drive LEDs requiring 8–18 V boost output - used in cellular phone keypad and display backlighting.
For engineers reviewing the LP3958TL/NOPB datasheet, LP3958TL/NOPB pinout, LP3958TL/NOPB application, or LP3958TL/NOPB equivalent, key selection considerations include programmable 8–18 V boost output voltage, I²C-controlled 8-bit current DACs for MAIN/SUB backlight dimming, independent keypad LED timing modes (overlapping/non-overlapping), thermal shutdown protection, and 25-bump DSBGA package compatibility with space-constrained handheld PCB layouts.
Technical Context
The LP3958TL/NOPB implements a current-programmed mode (CPM) boost converter with internal 1 MHz oscillator (set by external RRT), soft-start sequence, and four-layer protection: overvoltage, overcurrent, feedback break, and duty-cycle limiting. Its dual 8-bit IDACs control MAIN and SUB white LED strings independently or jointly (DISPL=1), enabling precise 0.1 mA-step current regulation up to 25.5 mA per string.
Keypad LED outputs (KEY1–KEY3) support three control methods: register-based brightness/balance programming, direct ON/OFF bit control, or external PWM via GPIO[0]/PWM pin. Mode selection (constant-current vs. switch) is controlled per-output via CC_SW bit, with saturation voltage ≥100 mV required for stable current sink operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Boost Output Voltage | Programmable 8–18 V in 10 discrete steps via 8-bit register; enables driving 3–6 white LEDs in series from Li-ion battery. |
| Main/Sub LED Current | 0–25.5 mA per string (8-bit DAC, 0.1 mA step); supports up to 4-LED MAIN + 2-LED SUB or 8-LED combined display. |
| Keypad LED Current | 0–15 mA per KEY output in constant-current mode (RKEY-set); 0–60 mA in switch mode with external ballast resistors. |
| Switching Frequency | 1.0 MHz ±7% (RRT = 82 kΩ); enables compact magnetics (e.g., 10 µH inductor) and low EMI with pulse-skipping elimination. |
| I²C Interface | Standard 2-wire interface (SCL/SDA) at VDDIO = 1.65–5.5 V; allows full register access for dimming, fade, enable, and fault control. |
| Thermal Protection | Internal thermal shutdown engages at TJ ≈ 150 °C and releases at ≈130 °C; prevents permanent damage during sustained high-power operation. |
| Package | 25-bump DSBGA (2.54 mm × 2.54 mm × 0.6 mm); optimized for ultra-thin portable PCBs with minimal board area footprint. |
Pinout & Package
LP3958TL/NOPB uses a 25-bump thin DSBGA package (YZR0025) with 0.4 mm pitch, exposing all terminals on bottom side. Thermal performance relies on GND bump array (GND, GND_SW, GND_KEY, GND_WLED, GNDT) and requires proper PCB copper pour for θJA = 60–100 °C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW | Boost power switch output | Drives external inductor; rated for 800–1150 mA peak current and 20 V max voltage swing. |
| FB | Boost feedback input | Monitors output voltage divider ratio; sets regulated boost voltage via internal error amplifier. |
| MAIN / SUB | White LED current sinks | Each delivers 0–25.5 mA with 5% tolerance at 12.8 mA; requires ≥400 mV saturation headroom. |
| KEY1 / KEY2 / KEY3 | Keypad LED drivers | Configurable as constant-current sinks (0–15 mA) or low-RDS(on) switches (~3.5 Ω). |
| VDD1 / VDD2 / VDDIO | Power supply inputs | VDD1/VDD2: 3.0–5.5 V core supplies; VDDIO: 1.65–5.5 V I/O domain for SCL/SDA/GPIO logic levels. |
| SCL / SDA | I²C interface signals | Support standard-mode (100 kHz) and fast-mode (400 kHz) communication; require pull-up resistors. |
| GPIO[0]/PWM | Multi-function I/O | Configurable as general-purpose input/output or external PWM input for KEY/MAIN/SUB modulation. |
| NRST | Active-low reset input | Asynchronous hardware reset; initiates register default state and internal startup sequence. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated high-voltage boost converter | Generates 8–18 V from 3.0–5.5 V input using internal 1 MHz CPM controller and SW pin - eliminates need for external controller IC. |
| Dual independent backlight drivers | MAIN and SUB 8-bit IDACs provide matched current regulation (0.2% matching when DISPL=1), enabling uniform brightness across multi-string displays. |
| Three programmable keypad LED outputs | Support overlapping/non-overlapping PWM timing, logarithmic brightness scaling (7-bit), and balance control - ideal for tactile keypad illumination with minimal MCU overhead. |
| Automatic fade-in/fade-out | Hardware-accelerated dimming with selectable 0.65 s or 1.3 s full-scale transition time; reduces visual flicker and enhances user experience without CPU intervention. |
| I²C-configurable operation | All functions - boost voltage, LED currents, fade timing, GPIO direction, PWM enable - are software-defined via 2-wire interface, simplifying system integration. |
Applications
| Cellular Phone Keypad Illumination | MP3 Player Display Backlight |
|---|---|
Use Scenario: Illuminating mechanical keypad buttons in GSM/CDMA handsets under variable ambient light conditions. IC Role / Device Role / Timing Role: LP3958TL/NOPB acts as standalone keypad LED controller, generating non-overlapping or overlapping PWM waveforms with programmable balance and logarithmic brightness scaling. Use Value: Eliminates MCU timer resource usage; achieves consistent 3-string LED intensity control with <3% current matching error and <1 µA leakage in standby. |
Use Scenario: Driving dual white LED strings for color-balanced LCD backlight in portable audio players. IC Role / Device Role / Timing Role: LP3958TL/NOPB serves as precision current source for MAIN and SUB strings, supporting joint control (DISPL=1) for 8-LED configurations with <0.2% matching. Use Value: Enables smooth 0–100% dimming via 8-bit DACs and hardware fade engine - no firmware PWM generation needed, reducing EMI and power consumption. |
| Digital Camera Status Indicators | PDA Main Display Backlight |
Use Scenario: Providing status feedback via discrete RGB or monochrome LEDs adjacent to camera controls. IC Role / Device Role / Timing Role: LP3958TL/NOPB operates KEY1–KEY3 in switch mode with external ballast resistors, delivering up to 60 mA per output for high-intensity indicators. Use Value: Supports fast ON/OFF toggling via register bits (K1SW/K2SW/K3SW) and external PWM modulation - enables blink patterns synchronized to camera shutter events. |
Use Scenario: Powering high-brightness transmissive LCDs in PDAs requiring stable, low-noise backlight current. IC Role / Device Role / Timing Role: LP3958TL/NOPB functions as integrated LMU, combining boost conversion, current regulation, and I²C interface in one 2.54 mm × 2.54 mm package. Use Value: Reduces BOM count by replacing discrete boost IC + dual LED drivers + keypad controller - saves >25 mm² PCB area and simplifies layout. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar lighting management applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61165DRVR | Single-channel WLED driver with integrated 38-V boost; no keypad LED outputs or I²C interface - analog dimming only. | Targeted at display-only systems without keypad illumination requirements; lacks fade, balance, or multi-string coordination features. | Select when only MAIN backlight control is needed and system MCU handles keypad timing; not suitable for LP3958TL/NOPB's dual-role use case. |
| LM3530TMX/NOPB | 4-channel I²C WLED driver with ambient light interface; no boost converter - requires external 18-V supply; no keypad driver capability. | Designed for adaptive display dimming using ALS input; cannot replace LP3958TL/NOPB's self-contained boost + keypad + backlight integration. | Choose if ambient-light-responsive dimming is critical and external high-voltage rail is available; incompatible with single-cell battery architectures. |
Compared with TPS61165DRVR and LM3530TMX/NOPB, the LP3958TL/NOPB uniquely integrates boost conversion, dual backlight control, and triple keypad LED management in one I²C-configurable DSBGA package - making it the only option for space-constrained portable designs requiring coordinated keypad/display illumination from a single Li-ion cell.
Availability
LP3958TL/NOPB is available at Aetrix Electronics and suitable for cellular phone keypad illumination, MP3 player display backlighting, and digital camera status indicator applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LP3958TL/NOPB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies, with decades of expertise in power management and portable system solutions.
The LP3958TL/NOPB belongs to TI's Lighting Management Unit product line, engineered specifically for battery-powered handheld devices requiring integrated high-voltage LED driving, minimal PCB footprint, and low-software-overhead illumination control.
FAQ
What is the maximum total LED current supported by the LP3958TL/NOPB?
The LP3958TL/NOPB supports up to 70 mA total continuous boost converter load current. This accommodates simultaneous operation of MAIN (≤25.5 mA), SUB (≤25.5 mA), and KEY1–KEY3 (≤15 mA each in constant-current mode). In practice, full-load operation requires careful thermal design due to θJA = 60–100 °C/W and internal thermal shutdown at ~150 °C junction temperature. The LP3958TL/NOPB datasheet specifies 70 mA as the absolute maximum continuous output current under defined test conditions.
Does the LP3958TL/NOPB require external components for boost converter operation?
Yes, the LP3958TL/NOPB requires external components for boost functionality: a 10 µH inductor (L1), Schottky diode (D1), input capacitor (10 µF), output capacitors (2 × 4.7 µF), feedback resistors (for FB pin), and timing resistor (RRT = 82 kΩ for 1 MHz). An optional EMI filter (RSW/CSW) is recommended near the SW pin. These components are explicitly called out in the LP3958TL/NOPB typical application circuit and electrical characteristics tables.
Can the LP3958TL/NOPB drive more than 4 LEDs in a single string?
No, the LP3958TL/NOPB is rated for up to 4 white LEDs per MAIN or SUB string, based on its 18 V maximum boost output and typical forward voltage of ~3.2 V per LED (4 × 3.2 V = 12.8 V). Driving 5 or more LEDs would exceed the 18 V limit under worst-case VF and temperature conditions. The LP3958TL/NOPB datasheet explicitly states "3 STRINGS OF 4 LEDS FOR KEYPAD" and shows MAIN/SUB driving 4-LED and 2-LED strings respectively - confirming 4-LED per string as the validated configuration.
How does the LP3958TL/NOPB handle thermal overload?
The LP3958TL/NOPB incorporates an internal thermal shutdown (THSD) circuit that disables all functions when junction temperature reaches ~150 °C and re-enables operation once temperature falls to ~130 °C. During shutdown, the device enters STARTUP mode and waits for thermal recovery before resuming normal operation. This behavior is documented in the LP3958TL/NOPB APPLICATION INFORMATION section and confirmed in Absolute Maximum Ratings (TJ-MAX = 125 °C continuous, THSD activation at higher transient threshold).
Is the LP3958TL/NOPB pin-compatible with other TI lighting management units?
No, the LP3958TL/NOPB is not pin-compatible with other TI LMUs such as the LM3530 or TPS61165. Its 25-bump DSBGA (YZR0025) package has unique pin assignments - including dedicated KEY1–KEY3 outputs, dual VDD supplies (VDD1/VDD2), and separate GND domains (GND_SW, GND_KEY, GND_WLED) - which differ fundamentally from alternate packages and signal groupings. The LP3958TL/NOPB connection diagrams and pin descriptions confirm no mechanical or functional pin mapping to other TI LED drivers.
LP3958TL/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 25-WFBGA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 5
- Voltage - Supply (Min):
- 3V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- 18V
- Current - Output / Channel:
- 1.15A (Switch)
- Frequency:
- 1MHz
- Dimming:
- I2C
- Applications:
- Backlight
- Operating Temperature:
- -30°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 25-uSMD
LP3958TL/NOPB FAQ
1.How can I place an order for LP3958TL/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP3958TL/NOPB on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LP3958TL/NOPB reliable?
The price and inventory of LP3958TL/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP3958TL/NOPB is usually 5 days.
3.What payment methods are accepted for LP3958TL/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP3958TL/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP3958TL/NOPB?
LP3958TL/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP3958TL/NOPB order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LP3958TL/NOPB?
For technical support, including LP3958TL/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP3958TL/NOPB requirements.
6.How does Aetrix verify that LP3958TL/NOPB is sourced from the original manufacturer or authorized distributors?
All LP3958TL/NOPB products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LP3958TL/NOPB meets industry standards.
7.What is the process for return or replacement of LP3958TL/NOPB?
All LP3958TL/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP3958TL/NOPB, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LP3958TL/NOPB part is unused and in its original packaging.
Return procedure for LP3958TL/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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